The City of Biddeford's financial records are audited each year by an independent auditing organization experienced in public accounting practices as a certified public accountant.  Formally referred to as an "annual post audit" or "single audit",  the audit serves to satisfy the requirements of the State of Maine Department of Audit and Title 30–A M.R.S.A. 5823, and Title 20-A M.R.S.A. Section 6051 dealing with local school audits, and a financial and compliance audit for all federally assisted programs in accordance with the Single Audit Act of 1984 (with amendment in 1996) and U.S. Office of Management and Budget (OMB) Circular A-133 and Compliance Supplements.

The annual audit reports from FY2004 through the most recent fiscal year are maintained by the Finance Department on the Annual Financial Reports webpage.